1. Field of the Invention
This invention relates in general to a thin-film inductive write head for magnetic recording disk drives, and more particularly to a write head with an improved pole tip structure.
2. Description of the Related Art
In a magnetic recording disk drive, data is written by thin film magnetic transducers called “write heads” that are maintained over the surface of the disk while the disk is rotated at high speed. Each write head is located on the end face of a head carrier or slider that is at least partially supported by a thin cushion of air (an “air bearing”) produced by the disk's high rotational speed. The surface of the slider that faces the disk is called the air-bearing surface (ABS) and the end face on which the write head is located is generally perpendicular to the ABS.
The write head has ferromagnetic pole pieces with pole tips that are exposed at the ABS. A nonmagnetic write-gap layer is located between the pole tips and an electrical coil structure is located between the pole pieces. When write current is passed through the coils a magnetic write field is induced at the pole tips across the write gap to magnetize or “write” regions of the recording layer on the disk.
A protective film, typically sputter-deposited carbon on an adhesion film, is formed on the ABS to protect the pole tips from corrosion. As the need for disk drives with higher data storage capacity has increased, the areal recording density of the disks has increased. This has led to the need for higher-moment ferromagnetic materials for the pole pieces, especially the pole tips, and for reduced magnetic spacing between the pole tips and the recording layer of the disk. However, higher-moment ferromagnetic materials have a higher film stress which can cause cracking of the protective film and thus corrosion of the pole tips. Thus the use of higher-moment ferromagnetic materials in the pole tips requires a thicker protective film which undesirably increases the magnetic spacing.
What is needed is a thin-film inductive write head with a pole tip structure that has the desired higher-moment ferromagnetic material but without the undesired thicker protective film.